Serial number (SN) is the ID of RMB, and some of the conterfeit RMB often has the same SN head (for example HD90XXXXXX).And the people's Bank of China has demanded all the bank using the banknote counter machine with SN recognition function. It is believed that in the near future, the governments of the major developed countries will require all banks to use the cash processing equipment with a serial number recognition function.
